Method of and means for starting dynamo-electric machines.



N5. 891,241. PATENTED JUNE '23, 1903.

B. FRANKENFIELD.

METHOD OF AND MEANS FOR STARTING DYNAMO ELECTRIC MACHINES. APPLIOATION FILED JAN.31,1907.

sf-Be it known thatjI, Bmrmmms,

BUDD'FRANKENHEnDQ F- nonwooi), OHIO, Assrsivon To ALLISZGHALMERS COMPANY, a

CORPORATION-OF NEW JERSEY, AND THEB-uLLooK ELECTRIC MANUFACTURING coM-.

. seamen-or m s'rnarmo nrirmo-nmcrmc mncnmns;

i Specification oi! Letters Patent.

PatentedI-Iun as, 1008.,

itpplicationiiledl'ahuaryal,1507. seminasaama To all whom it my concern: A

a citizen of the United States residing at Norwood, in p the county of l I-Iamilt'on and State of Ohio, haveinvented certain new and useful Improvements in Methods of and Means for Starting Dynamo-Electric Machines, of which the following is a full, clear, and exact specification.

My invention relatesto the method of and means for starting s chronous electric nae-- chines, such as sync onous motors and rotary converters, and its object is toprovide a simple arrangement wherebysuch machines. may bebrough-t tosynchronism and thenconnected to t e mains. t v 5 Mg invention broadly consists 'of the met d of starting a synchronous electric machine, which consists in driving such machine near synchronism' by an auxiliary driving source, causing said auxiliary source to vary in speed tobring such machine nearer to synchronism, and connecting said machine to the source of current when it comes substantially into synchronism therewith.

More specifically my invention consists of a. rotary. converter, switches for connecting.

, said converter to alternating and-direct cur-1 rent mains respectively, an auxiliarymotor arranged to drivesald converter above syn a rheostat arranged to be connectiliary motor to slowit down to bring the ro- I diagrammatic invention.

tary converter into synchronism with the alternating-current mains, and means for indicating t e phase relation of the converter and said source of'current. 1

Other features of my invention will a pear from the description and drawings an articill'arly pointed out in the claims.

e singh i rfifiure of the drawings shows a y one embodiment of -my Referring now to the drawings 5', B and 7- represent. three-phase alternating current mainsarranged tobe connected by a switch 8 to the 'former.

former isarranged to be connected by a rimary 9 of a threehase transihe secondary 10 or:.;thej transswitch ll to the slip rings 12 at th ealternat" ing current end of arotary converter 13 and by a switch 14 to a self-starting alternating resented. as a three-phase induction motor,

in any desire manner to drive the rotary started with t e motor 15, will'be slightly current motor 15. The motor 15 is here repthough any other type of motor may be used. The direct current end of the rotary con- ,ver'ter is arranged to be connected by a switch '16 to the direct current mains 17 and 18, or by a-sw'itch 19 to arheostat 20'. For reasons hereafter apparent, this rheostat 20 will be referred toas the synchronizing rheo stat. The directcurrent side of the rotary converter also su plies its field'winding 21, this field winding iieing adjustable instrength by a rheostat. 22.

The motor 15 and the rotary converter 13 may be connected to ether by a clutch 23 of any desired t e. v T e motor 15 isv arranged converter 13 somewhat above its synchronous speed. A switch 24is arranged to con nect so-called synchronizing lamps 25- across one phase of the alternating current circuit, around the switch 11. These lamps ma be arranged to indicate similarity of ,p ase "either on the darlg or light, though here shown as doing so on the dark. Any other form of synchronizing device ma be used if desired. A vo'ltmeter26shou1d. e provided for indicating the voltage'of the rotary cons verter 13 This voltmeter may. be connected to either end of the rotary converter and is hege sho'wn connected to the direct current en The operation of the system is as follows:. Theswitches 8., 11,14, 16, 19 and preferabl 24 should be-o en. The clutch 23 is close U on closing t e switches 8 and 14, referab y successivel current is supplied t ugh the transformer 9, 10 'to the auxiliary .or starting motor 15, causing it to start and ac celerate until it has attained its normal s eed when the rota converter 13, which has een above synchronism. The-field 21 is now built up to approximately normal value as indicated vby e voltmeter 26. If previously opened, the switch24 should now be closed to'connect in-the synchronising lamps 25. By closing the switch 19, the'synchrm nizing rheostat 20 is connected across the di rect urrent; end of the-rotary" converter 13 and may be adjusted toputas'g'reat a load as desired on itand the auxiliary motor 15, thus gradually siowin "-them down. the -rotary converter sfows down and s more nearly in synchronism withthe sting current mains, the pulsations of the lamps 25 become slower and slower. When these pulsations are su'fficicntly slow, the switch 11 is closed as the lamps 25 approach or reach darkness, at which time the rotary converter is approximately in phase with the alternatcurrent mains. The interchanges of current between the alternating current mains and the rotary converter will now keep the latter in synchronism. Since the motor 15 is of no further use, it may be disconnected from the rotary converter 13 by opening the clutch 28 and may be stopped by opening the switch 14. The switch 19 is now opened to disconnect the synchronizing rheostat 20,

7 after which the voltage of the rotary converter is properly adjusted by the rheostat 22, and the switch 16 may be closed to connect the direct current end of the rotary converter to the direct current mains 17 and 18. If desired, the switch 24 may also be opened to disconnect the synchronizing lam s 25, thou h this is not necessary as these amps are s ort-circ ited by the switch 11. The rotary converter 13 will now operate to transfer current from the alternating current mainsto the direct current mains or vice versa as required.

Instead of having three-phase alternating current for the alternating current side of the rotary converter, alternating current of any desired number of phases may be used. Moreover, a motor generator set may be used instead of a rotary converter.

Ammeters, power factor meters and the like may be used when desired, these being omitted from the present drawing for the sake of simplicity. Interlocks between the various switches may be used if desired.

Many other modifications may be made in the recise arrangement shown and described in t e s ecification and set forth in the following c aims.

What I claim as new is 1. The method of starting a synchronous electric machine, which consists in driving such machine above synchronism by an auxiliary driving source, causing said auxiliary source to decreaze in speed gradually, and connecting said machine to the source of current when it comes substantially into synchronism and phase therewith.

2. The method of starting a synchronous electric machine, which consists in driving such machine above synehronism by an auxiliary driving source, gradually increasing the load on the driving source to decrease its speed, and connecting said machine to the source of current when it comes substantially into synchronism and phase therewith.

3. The method of starting a rotary converter, which consists in driving it above synchronisni by an auxiliary motor, loading the rotary converter gradually to decrease the speed of the auxiliary motor, and constantially in step with the electromotiveforee therein.

5. The method of starting a synchronous motor, which consists in driving it above synchronism by an auxiliary motor, loading the synchronous motor to slow down the auxiliary motor, and connecting the synchronous motor to the source of supply when it is approximately in synchronism and phase therewith.

6. The method of starting a rotary converter, which consists in driving it above synchronism by an auxiliary motor, connecting a variable resistance across the direct end of the rotary converter and varying said resistance to slow down the auxiliary motor, and connecting the alternating current end to the alternating current mains when it is substantially in step with the electromotive force therein.

7. The method of starting a synchronous electric machine, which consists in driving it near synchronism by an auxiliary motor, varying the load on said auxiliary motor to vary the speed in the proper direction to bring said synchronous machine substantially to synchronism, and connecting said synchronous machine to the source of current when it is substantially in step therewith.

8. The method of starting a rotary converter, which consists in driving it near synchronism by an auxiliary motor, varying the load on the direct current end of the rotary converter to vary the speed of the auxiliary motor in the proper direction to bring the converter closer to synchronism, and connecting the alternating current end of the rotary converter to the source of supply when it is substantially in step therewith.

9. In combination, a rotary converter, an auxiliary motorarranged to be connected to said converter to drive the latter above synchronism, means for increasing the load on the auxiliary motor to slow it down and bring the rotary converter nearer to synchronism, a device for indicating when the rotary converter is in phase, and a switch for connecting the rotary converter to an alternating source.

10. In combination, a rotary converter, an auxiliary motor for driving said converter above synchronism, a rheostat arranged to be connected across the direct current end of the rotary converter to cause the auxiliary of supply.

auxiliary motor arranged to drivesaid conmotorto slow down to bringthe rotary converter closer to synchronism, and means for connecting the rotary converter to the alternating current source.

11. In combination, a synchronous motor, an auxiliary source of power arranged to drive said motor above synchronous speed, means for causing said auxiliary motor toslow down to bringthe synchronous motor more nearly to synchronism, and means for connecting thesynohronous motor to asource 12. In combination, a rotary converter, an-

verter, means for varying the load on the di- 15 for indicating when the rotary converter is in step, and means for connecting the two ends q of the converter to alternating and 'direct current sources respectively.

In testimony whereofI aflix my signature in the presence of two witnesses.

BUDD FRANKENFIELD. 

